Building with arches_vaults_cuppolas 1994

2 The Basics of Building with Arches, Vaults and Cupolas
The Basics of Building with Arches, Vaults and Cupolas
A SKAT publication, Swiss Center for Development Cooperation in Technology and Management, 1994.
Authors: Thierry Joffroy, assisted by Hubert Guillaud, architects researchers, CRATerre-EAG
Contributions by: Patrice Doat, Alexandre Douline, Josep Esteve, Philippe Garnier, Hugo Houben, Serge
Maïni, Pascal Odul and Vincent Rigassi of CRATerre-EAG.
and with the opinions of: John Norton, Development Workshop ; Roland Besenval, CRAO-CNRS ; Myriam
Olivier, ENTPE de Lyon ; Gernot Minke, University of Kassel ; Kiran Mukerji,
Planning and Building in the Tropics. Editing by Karl Wehrle and Heini Müller; SKAT
Available at: SKAT-Bookshop, Vadianstrasse 42, CH-9000 St. Gallen, Switzerland,
Fax. +41 71 23 75 45
The town of Thera, on the island of Santorin in the Cyclades, Greece

The Basics of Building with Arches, Vaults and Cupolas 3
CONTENTS
Project of the architect Hassan Fathy, villa at Fayoum, Egypt, 1984

ARCHES, VAULTS AND CUPOLAS
A thousand-year old
technology
The use of arch, vault and cupola
building systems in construction can
be traced back to most ancient
times. As early as the 3rd millenium
BC, they were very widely used in
the countries of the Middle East and
Egypt.
Arches, vaults and cupolas were
also fairly widely used by Roman,
Sassanid and Byzantine builders
before being adopted in many
regions of Europe.
Very many applications also
emerged in North Africa, the Sudan-
Sahel belt of Africa, as well as in the
northern regions of China.
Many of these countries still boast a
rich heritage of this kind of building,
both in urban and in rural areas. In
many cases, building them is still a
living tradition, well suited to modern
popular housing needs.
Recent projects
Forgotten by the formal building
sector since the appearance of
concrete, arches, vaults and cupolas
were rediscovered in the 40’s by the
Egyptian architect, Hassan Fathy,
who found inspiration in the popular
Nubian tradition for the design and
construction of the village of New
Gourna.
The international success of this
project, and of other Hassan Fathy
achievements, rekindled a renewal
of interest amongst architects.
Realizing the significant potential of
these architectural models, some
development project managers have
re-launched the use of arches, vaults
and cupolas.
These programmes, have enabled
the construction of many buildings
meeting the varied needs of different
countries.
Diversity
The numerous types of arches,
vaults and cupolas allow a great
variety of architectural models.
As a result, the technology can adapt
to the most varied climatic condi-
tions: zones which are arid or rainy,
cold or hot.
Although arches, vaults and cupolas
are traditionally used to cover limited
spaces, they are perfectly well-
suited to build much larger spaces,
up to tens of meters. Thus they can
meet the needs of any building
programme, public or private, low-
cost or quality housing, granaries,
warehouses, shops, schools, public,
religious buildings, etc.
House built with "Nubian vaults" in adobe bricks near Aswan, Egypt

TRADITION, PRESENT AND FUTURE
Suitability
Arches, vaults and cupolas can often
provide a good solution for covering
all kinds of buildings of all sizes.
However, their acceptability and
suitability to genuine needs and local
climatic conditions cannot always be
taken for granted.
This means that preliminary surveys
are required. These enable one to
choose the correct option and select
suitable technical solutions.
In order to ensure that structures are
well designed and well built, special-
ized training must be given at all
levels: design, engineering and
construction.
Mastering the technology
The experience acquired over the
last twenty years has allowed the
design and construction of buildings
using arch, vault and cupola
structures to be mastered once
again.
The technology is now used in
several areas of the world: the Sahel
belt of Africa, the Near and the
Middle East, India, Central America.
Initially launched in Niger, the
“Woodless Construction” pro-
gramme suggests simple technical
solutions, well-suited to the local
context, and follows a policy of
research and training which ensures
a major impact amongst local people.
Winner of the “Habitat” Award
1992, this programme is now spread-
ing to other countries of the Sahel.
Research and development
Even though arches, vaults and
cupolas are already well known,
research and development pro-
grammes are being carried out,
mainly in four areas:
1 - systematic identification of
models and types, and the various
ways of using them ;
2 - suitable tools to substitute for the
know-how of traditional builders ;
3 - perfecting simplified methods of
calculation ;
4 - techniques to prevent rainwater
infiltration: water-proofing, run-
off, surface maintenance.
Project of the architect Hassan Fathy, built in 1981 in New Mexico, USA

ARCHES, VAULTS AND CUPOLAS
Deficiency of traditional
roofs
In many countries, good quality
wood required for the construction
of traditional roofs is no longer
available in sufficient quantities. This
results in the use of poor quality
wood, imports, or even turning to
conventional modern techniques
such as woodworks covered with
corrugated iron sheets or concrete
slabs.
Gradually these conventional modern
techniques have emerged as the only
alternative to traditional ones.
Disadvantages of
conventional modern
technologies
Industrial products such as asbestos
sheets and corrugated iron are not
always well suited to local conditions
(heat, cold, noise, appearance, etc.)
Often imported or even produced in
centralized units, they encourage low
skill levels more than job creation.
Building systems based on the use of
reinforced concrete consume large
amounts of expensive materials
such as cement, steel, timber for
formworks, as well as sand and
gravel which are not always locally
available. This places them out of
reach of the vast majority of local
inhabitants.
An alternative
Traditional techniques, adaptations of
these, or newly imported techniques
do not always provide a solution to
roofing needs in harmony with local
conditions: cultural, climatic or even
economic.
As a result, alternative roofing
solutions are needed. Building with
arches, vaults and cupolas is, in
many instances, one of these solu-
tions.
Their numerous variations and wide
range of architectural solutions
enable them to be adapted to very
diverse situations.
Advantages of arches,
vaults and cupolas
The materials used for the construc-
tion of arches, vaults and cupolas
can be the same as those used for
walls and can be found or produced
locally. Construction is therefore less
expensive, creates jobs and allows
foreign currency savings.
There is no use of wood, which also
totally eliminates the risks of fire.
The massive nature of these struc-
tures provides good heat storage
capacity and delay in heat transmis-
sion, meeting comfort requirements,
especially in dry climate regions.
This mass also gives good sound
insulation.
Research centre, Dakar, Senegal
Information and reception centre of Auroville, India;
International Hassan Fathy Award 1993

ADVANTAGES AND POSSIBILITIES
Economic considerations
The cost of buildings using arches,
vaults and cupolas varies according
to the materials employed, the
complexity of the design and of the
construction technique, the size of
the structures, and the surface
protection used.
However, buildings employing sun-
dried earth bricks (adobe) and
protected with an earth render can
be built at a lower cost than
traditional buildings of a similar
standard.
In general, arches, vaults and
cupolas made from water-resistant
materials and protected by durable
water-proofing cost more than
simple buildings covered with roof
sheeting, but remain less expensive
than buildings with reinforced
concrete slab roofs.
Job creation
Building with arches, vaults and
cupolas is highly labour intensive.
Therefore, the technology has great
job creation potential, not only with
regard to construction, but also with
regard to building materials produc-
tion.
Foreign currency savings
The basic materials are generally
available on site, and little power is
required for processing them.
Significant foreign currency savings
are possible. Transport costs are
also reduced.
The investment in site equipment,
centering, compass, scaffolding, is
generally very small, and most of
these can be manufactured locally
without any major difficulty.
Crossed arches, Zaria, Nigeria
Great aesthetic potential
The many possibilities of forms,
sizes, combinations of different
elements and types of finishing
enable highly attractive spaces to be
created. Thus arches, vaults and
cupolas can be used not only for
low-cost housing programmes, but
also for high quality, luxury
dwellings.
Limitations of use
Some local conditions can limit the
benefits of building with arches,
vaults and cupolas:
l rejection by the inhabitants for
cultural reasons,
l high cost of labour,
l high cost of suitable building
materials,
l use in earthquake areas requires
special care,
l lack of building norms.
The technology must be adjusted to
a given context and the techniques
must be mastered, to warrant the
advantages of using arches, vaults
and cupolas.
"Woodless construction" project in Niger: simple but adapted structures

ARCHES AND THEIR USES
Forms of arches
There are many shapes of arches.
These are mainly characterized by
the curve of the intrados and the
ratio of height to span.
Most arches are connected to the
wall by the extrados. The corbel
arch, built using courses gradually
jutting further out, and monolithic
arches, whether poured, tamped or
cut out, have no extrados and
continue directly on from the wall.
A partition arch (3) serves as a
loadbearing element in a large room
by supporting roofing elements of
restricted length, joists, purlins or
even vaults or cupolas.
An arch can serve directly as the
springer of a cupola (4). In this case
the forms of the arch and of the
cupola are closely interlinked.
Varied uses of arches
The main function of an arch is to
bridge an opening in a wall.
By juxtaposing and repeating arches
resting on pillars, one can obtain
arcades (1), which allow one to
create very open covered spaces.
Arcature, or blind arches (2), can be
used to lighten the masonry structure
or simply for decorative purposes.
(1)
(2) (3) (4)

VAULTS
Forms of vaults
There are a great many forms of
vault. The simplest are barrel vaults
which in fact consist of a succession
of identical arches. Barrel vaults can
have steeper or flatter profiles: semi-
circular, segmental, ogival. etc. The
catenary vault is very common as its
form gives maximum stability for a
minimum use of material.
Combining two barrel vaults with the
same profile allows two other types
to be defined: the “groined vault”
and the “Dominical vault”. By
prolonging one of the two barrel
vaults, the “Dominical vault”
becomes a “trough vault”. Combin-
ing barrel vaults with different
profiles forms a “lunette vault”.
A “Dominical vault”, the ribs of
which are rounded in the form of
cones starting from the corners,
becomes a “squinch vault”. Similarly
the “trough vault” can evolve into a
“boat vault”.

CUPOLAS
Forms of cupolas
Cupolas are obtained by rotating an
arch, except for faceted cupolas
which more closely resemble the
Dominical vault. A cupola can be
semi-circular, segmental, ogival,
conical, etc.
Cupolas are circular in plan. They
can, however, be used to cover
square or rectangular rooms by using
pendentives or squinches. Cupolas
on pendentives can be used to cover
any kind of polygonal shape in plan.
It is possible to combine several
cupolas or to combine cupolas with
vaults.

USES OF VAULTS AND CUPOLAS
Varied uses
Vaults and cupolas cover spaces
either with or without recourse to
walls or other supporting structures.
They are, however, merely struc-
tures. They become a roof-covering
only if they are given a waterproof
coating.
Flat or slanted roofs and flooring can
be easily obtained by infilling the
rounded forms.
Small span barrel vaults built
between girders, known as vaulting
cells or jack arches, can be used for
flooring.
Rural housing near Lake Titicaca, Bolivia Adobe vaulting cells
Civil servant accomodation, Kamboincé, Burkina Faso
Stone barn with flat-stone roof, Causse Méjean, France Farm building using several levels
of ribbed vaults, Queyras, France

DEVELOPMENT PROJECTS
Housing and development
In the context of applying a develop-
ment policy, programmes implement-
ed by government and non-govern-
ment organizations aim not only to
produce buildings, but also to have a
spin-off effect on people’s socio-
economic situation.
Apart from the requirements of
housing programmes, job creation
and the preferential use of local raw
and building materials are the main
technical objectives that building with
arches, vaults and cupolas can meet
perfectly.
Preliminary actions
Preliminary surveys, as well as
various stages of experimentation
and training, will ensure a successful
implementation.
Where no tradition exists, prelimi-
nary surveys represent a significant
investment. As a result, organiza-
tions play a major role, as sufficiently
wide programmes enable this
investment to be amortized.
Implementation
The implementation of a building
programme should always form part
of a development approach and
strategy.
In all cases, the professional training
which is given during project imple-
mentation is an asset which can
benefit the whole community.
Involving local tradesmen, entrepre-
neurs, architects, engineers and
draftmen, ensures the possibility of
spontaneous and correct replication
of the building models proposed and
their dissemination.
Spontaneous replication of models is a sign of a development project's success; "Woodless construction"
programme, Niger

BUILDING MARKET
Focus on building materials
cupolas highlights the potential of the
building materials used. Demonstra-
tion structures and designs allow
their quality to be illustrated and their
credibility amongst the public to be
reinforced. This can strongly
counterbalance resistance to new
materials in the marketplace.
Focus on enterprises
Because it calls for technical knowl-
edge and skills, which non-profes-
sionals always find impressive, it also
focuses on the enterprises involved
and confers upon them a favourable
quality image.
Quality
The quality of a building depends on
the quality of the basic materials and
of the building work. The durability
of the structure will be linked to
surface protection or water-proofing
being carried out well.
To ensure the quality and durability
of the building, the contractor should
carefully control site supplies and
work. In addition, the client should
be informed about any required
maintenance of the surface protec-
tion, frequency and technique.
New markets
Launching into building with arches,
vaults and cupolas can open new
markets, public or private, especially
if the launch takes place in conjunc-
tion with pilot promotion programmes
run by organizations.
Investment
Investment is generally very low as
the equipment required is simple and
can be manufactured locally.
On the other hand, in order to ensure
a good quality of his achievements,
the entrepreneur will have to invest
in training his employees. This
investment will be balanced by the
quality of the realization.
An attractive technology; private house, Marrakesh, Morocco

KEY QUESTIONS
If you are interested in building with arches, vaults and cupolas, you should be aware of the
implications that follow on, with regard to:
l acceptability of architectural models,
l building materials,
l buildingskills,
l costs, management and investment .
10 key questions
1 - Is there a demand for an alternative roofing solution or for an improvement in traditional
techniques of building with arches, vaults and cupolas?
2 - Do you think the people would accept buildings made with arches, vaults and cupolas?
3 - Are suitable building materials available locally or can they be produced?
4 - Do you have a suitable solution for surface protection or water-proofing?
5 - Are you aware that all types of roofing systems need periodical maintenance?
6 - Do you realize that it may be necessary to revise your building methods as a whole?
7 - Is your region prone to specific building problems like earthquakes or swelling soils ?
8 - Are you prepared to make an investment in equipment and in technical surveys?
9 - Are you prepared to pay particular attention to training?
10 - Do you know where you can find technical and training support?
Exhibition centre, Janadriyah, Saudi Arabia

RECOMMENDATIONS
If by assessing the ten key questions you conclude that there is a potential to construct arches,
vaults or cupolas, it is recommended to make a fine-tuned feasibility study. This should be made
also in order to elaborate a programme of activities ensuring a successful building with arches,
vaults and cupolas.
Feasibility study
It should be conducted on the following main aspects:
1 - Socio-cultural: demand analysis, acceptability amongst local inhabitants,
2 - Economical: living standards, costs, credit, market, loans,
3 - Technical: structural and surface protection materials, statics, norms
in force,
4 - Climatic and geographical: weather, environment, natural calamaties,
5 - Institutional / entrepreneurial: organisations, policies, capability and means,
6 - Skill and know-how: experiences, know-how transfer, training possibilities
Further steps
Based on the data gathered through the feasibility study, it will be possible to elaborate recommen-
dations and a strategy of work. From experience, a special attention has to be paid to the following
aspects:
1 - Architectural choices:
These should be made taking account of cultural references.
2 - Technical choices:
They must be adapted to the specific local conditions. The degree of complexity of the building
principles, their flexibility, and their replicability must be taken into account.
3 - Demonstration:
Test buildings must be erected. These enable the acceptability of the proposed models to be
verified, the technical and architectural choices to be refined, and the overall level of skills and
knowledge, and therefore of the quality of built examples, to be improved upon.
4 - Professional training:
This should be provided at all levels in order to create teams capable of undertaking projects
from design to building stage, as well as the maintenance of the buildings.
5 - Quality control:
Good supervision has to be put into place in order to ensure the quality of the constructions.
6 - Technical assistance
For a minimum period, keeping in regular contact with partners who are experienced and able to
give technical help or advice is recommended.
7 - Commercialisation:
Promotional and commercial activities might be necessary in order to ensure the minimum
quantity of work allowing the amortisation of your investments in the technology.

BUILDING OPTIONS
AND ARCHITECTURAL / ENGINEERING DESIGN
Choosing between options
Each arch, vault and cupola has
specific properties and technical and
architectural capabilities. Therefore,
it is important to have a good
understanding of the various “fami-
lies” of building systems and the
architectural possibilities which
follow on from these, in order to be
able to make a relevant choice
between options. Such choices,
indeed, have a very great influence
on the acceptance and the appropri-
ation of the technology. Therefore,
attention has to be taken in order to
meet all the different facets of the
needs and constraints of a construc-
tion.
Building
The various forms of arches, vaults
and cupolas are closely linked to one
or more building methods. They are
more or less inexpensive, depending
on how much specialized equipment
is needed and how difficult the
construction work is. The issue of
scaffolding is also an important
factor and can determine the pre-
ferred dimensions, notably for the
height of the arch, vault or cupola.
Spatial considerations
The curved forms generated by
arches, vaults and cupolas define
free variable heights which increase
with the span and the rise.
Depending on requirements, one
should first determine the curvature
of the element and the height of its
spring-point.
The ability to move between one
space and another also makes it
important to take account of the
ability to open out between the
interior and the exterior of a vault or
of a cupola. One can distinguish
between open, semi-open and closed
types.
Building complexity
Building systems using arch, vault
and cupola structures can range
from the simplest to the most
complex. The main distinction to be
made is between modules which are
independent from one another
(whether connected or not) and
sophisticated systems which respect
very precise geometrical traces.
The sophisticated systems enable to
get an optimum use of the material
and perform very well from the point
of view of costs. On the other hand,
their replicability can be tricky as a
high degree of precision at the laying
out stage is required.
As a general rule, the more the
shapes of the vaults or the cupolas
are visible, the cheaper the building.
Certain models permit a simple and
inexpensive transition to flat or
sloped roofs.

Architectural appearance
Arches, vaults and cupolas offer a
very great number of architectural
possibilities with a more or less
typical and attractive character.
These depend on the materials and
models used, the methods of utilisa-
tion, and finally the building tech-
niques which are linked to them. The
architectural aspect is one of the
principle vectors of cultural and
social acceptability of a technology.
Acoustics
The rounded shapes, especially of
cupolas, can result in a significant
degree of reverberation which is an
asset or a disadvantage depending
on the intended use of the space.
Simple measures, such as corbelled
elements or suspended cloth, can be
used to reduce reverberation.
Stability of arches, vaults
and cupolas
To ensure stability, the form should
be as close as possible to the line of
force. In the case of vaults, for
evenly distributed loads, the best
form resembles that of an inverted
suspended chain (catenary). This
applies both to flatter and to slender
forms.
The corresponding ideal cross-
section of a cupola is somewhat
different and can only be worked out
graphically or mathematically.
Combining vaults and cupolas results
in more complex issues of stability
and allows much more flexibility in
shape.
Stability of supports
Arches, vaults and cupolas are
heavy roofing elements and they
exert thrusts which increase with the
degree of flatness, the span and the
weight of the structure. These
thrusts may be concentrated or
dispersed. They have a tendency to
push out the supporting bases (walls,
piers and foundations) and must be
taken into consideration. The most
common solutions are: cancelling
them out by juxtaposition, widening
the wall, buttresses, and tie-beams or
ring-beams.
Details and finishings
Details and finishings can influence
the choice of structure. Attention
must be paid to:
- the bonding pattern(s), particular-
ly for visible masonry,
- channelling and removal of
rainwater,
- window frames.
Forms of "inverted chain"
Segmental arches exert greater
thrusts than slender arches
Section of house in Sfax, Tunisia
Designs for various shapes of
building:
curved, flat or sloping roofs Project for a 2 classroom block, Senegal
Section of church, Valladolid,
Spain

BUILDING MATERIALS
The building materials required for
the masonry of arches, vaults and
cupolas can be divided into two
broad groups: solid components
(adobe, stone, etc.) and binder
components (mortar). The solid
components ensure compressive
strength. The binder components
ensure that compressive forces are
transmitted and the cohesion of the
whole.
To avoid the risk of shrinkage during
drying out after building work,
preferably a minimum amount of
binder component should be used.
The various solid and binder compo-
nents are rarely incompatible but it is
preferable to use components of
similar strengths.
Solid components
Stone:
Stone is often of very irregular
dimensions, which forces one to use
very expensive preparation and
implementation techniques. Soft, light
stone offers interesting possibilities,
as does layered stones, which can be
standardized by simply chiselling
them to the required shape.
Adobe block:
Simply prepared by moulding plastic
soil and leaving it to dry, the adobe
block is always inexpensive. Its
shape and size can be easily
adapted to the various methods of
construction, so that this material is
the most widely used. However, its
rather low mechanical performances
require the construction of fairly
massive structures.
Stabilized compressed earth
block:
Being insensitive to water and
having good mechanical strength,
this material provides an alternative
to the more costly fired brick. Most
of the presses used to manufacture
compressed earth blocks can be
adapted to produce special blocks.
Plain moulded cement blocks:
Made from sand-cement mortar,
these blocks have been used for
very diverse buildings as many
shapes and sizes of both simple
elements, and also of special parts,
can be prepared.
Fired solid brick:
This material is more expensive but
generally performs well, which
allows for either lighter buildings or
larger dimensions. Special shapes
and sizes can be obtained, depending
on the means of production.
Fired hollow brick:
This enables special application
techniques to be used, and very light
buildings to be realized. Materials
produced using craft pottery
methods can be used in a similar
way.
Binder components
Earth mortar:
This is used to bond adobe, fired
brick or stone. Its good sticking
properties enables one to build vaults
and cupolas without shuttering.
Plastic earth mortar can be used to
make hand-shaped cupolas.
To avoid shrinkage, straw or sand is
added to soils with an excessive clay
content.
Stabilized earth mortar:
Cement, lime, plaster or bitumen
improve the characteristics of earth
mortar. Such mortars are very
suitable for binding compressed
earth blocks or fired bricks.
Lime-sand mortar:
This displays average
characteristics; its main advantage is
that it stays malleable for quite a
long time and sets very slowly. It
can be improved by adding crushed
brick or pozzolanas. Lime-based
mortars are very frequently used in
conjunction with fired brick and
stone.
Cement-sand mortar:
Given the high cost of cement, the
amount used must be carefully
calculated according to the mechani-
cal strength required. This mortar is
suitable for bonding good quality
fired earth and full sand-cement
blocks. Having little adherence, it is
not well suited to shutterless building
methods, apart from corbelling.
Medium-span vaults have been
made directly using a sand-cement
mortar.
Small size elements can be prefabri-
cated.
Moulding an adobe block into the
shape and size required

Gypsum mortar:
This sets very quickly, which enables
adhesive application techniques to be
used.
Small span vaults can be made or
even prefabricated directly using this
mortar.
The stability of water-soluble
gypsum can be improved by combin-
ing it with lime.
Surface protection
To avoid infiltrations and therefore
risks of detoriation,vaults and
cupolas must be protected from
rainwater, which must be channelled
away from the building, using water-
spouts or downpipes.
Renders:
An earth render is the least expen-
sive, but requires periodical mainte-
nance whose frequency which
depends on the nature and the
quantity of rainfall. .
A sand-cement mortar is too rigid
and will always crack, which allows
water infiltration to take place. It
should not be used without a comple-
mentary membrane.
Lime-sand and gypsum-lime-sand
renders are better suited because of
their greater pliability, but a certain
amount of maintenance might still
needed.
Roof coverings:
Certain forms of vaults and cupolas
can be protected by roof coverings
made of thatch, flat stones or even
tiles. Although rarely used in recent
projects, these solutions can be very
efficient while remaining cheap.
Membranes:
Membranes consisting of a single or
multi-layer bitumen-based material,
of waterproof paint or of metal
leaves are efficient, but often too
expensive.
Flat and sloping roofs:
A great many solutions are possible
here, but the choice of the shape of
the vault will be crucial to the
simplicity of implementation and to
economic considerations. The
simplest solution is to use a compact-
ed earth and gravel infill, on which
the water-proof layer is placed, but
solutions including very light wooden
structures are also possible.
Earth plaster is efficient but often
requires maintenance
Ensuring water run-off through a
water-spout
Tiled roof cover
Multi-layer water-proofing

EXECUTION
Building arches
With formwork:
For building an arch, a formwork of
the same shape of its intrados needs
to be used. This can be made of
wood or metal and should be used in
conjunction with a system allowing
its easy removal.
For most arch forms, the formwork
can be removed immediately after
construction. The formwork can
therefore be reused straightaway.
This means that if there are a great
many identical arches to be built,
clearly it makes sense to prepare a
precise and robust formwork to
ensure that it can be reused and that
the work will be of high standard and
carried out quickly and economically.
Building up bricks or blocks with dry
joints and shaping the curve with a
layer of mortar is a very economical
way of making a formwork.
Without formwork:
Corbelled arches are built using
courses which each jut out further
than the previous one. Cut out
arches, and arches shaped with
wooden reinforcement, are also built
without formwork.
Building vaults
Vaults can be built in a similar way
to arches.
With formwork:
Building can be done on a full
formwork set up in place. This is
mainly used for floors over base-
ments.
It is possible to use an integrated
formwork. Being very heavy, this
has to be assembled and dismantled
in place. This technique is
economical only if the vaults - and
therefore the formwork - are light.
Sliding formworkBrick formwork
Wooden formwork
Metal formwork
Corbelled arches

Sliding formwork:
Building takes place in stages, with
the formwork being repositioned as
often as necessary. This is one of
the most interesting methods, but
applies only to barrel vaults.
Without formwork:
Corbel vaults can be built only using
small spans.
Building in so-called “slices”, without
formwork, is the most economical
method. This exploits the properties
of certain mortars which enable the
bricks to be laid face on layers
leaning at a steep angle to the
vertical. To improve adhesion, small
and fairly thin elements of regular
dimensions should be used.
Using this principle, and by varying
the shape and the size of the
courses, one can build barrel,
groined, dominical, trough, squinch
and boat vaults.
Traditionally, all these vaults are built
“by eye”, but light tools can be used
to guide the masons so that they
build the required shape correctly.
TOOLS AND SKILLS
Building cupolas
Building techniques without form-
work are always prefered as a
formwork would be too complicated
to manufacture.
Corbelling:
This enables large areas to be
covered, but results in conical forms
which are very high relative to the
span.
Increasingly inclined rings:
Horizontal rings which gradually
decrease in diameter can be used to
create all types of cupolas. This
method uses the same brick-laying
technique as for vaults built in
“slices”.
Simple rotating guides which de-
scribe the form in the air can be
used to obtain correct, regular forms.
Hand shaping:
Using a straw-reinforced earth
mortar, it is possible to build fairly
large sized cupolas. These are built
up in successive layers.
Squinch vault
Building a barrel vault in "slices"
Building a cupola using inclined ring-courses

PROFESSIONAL TRAINING
After theoretical training, learning on site is vital to acquire real skills
The need for training
Current training courses teach very
little about the particularities of
arches, vaults and cupolas and about
techniques to build them. Specific
professional training has to be
provided for all concerned, from
designer to builder.
“Design know-how”
Designing buildings with arches,
vaults and cupolas calls for specific
engineering knowledge, principally
including spatial geometry and
principles of stability. The various
technical solutions or architectural
variants also need to be known in
order to enable the technology to be
adapted, to be used creatively and to
evolve.
“Building know-how”
Although the main masonry princi-
ples apply, specific building tech-
niques must also be used. Even
though these call for some tricks of
the trade and specific tools to be
used, these techniques are quite
simple, and they can be mastered
very quickly.
Structural principles should also be
well understood, so that adaptation to
special or new situations can occur.
Although formal training will always
remain the most efficient, on-the-job
training on sites supervised by
qualified staff is a good way of
acquiring practical skills at an
affordable cost.

PROJECT MANAGEMENT
The market
The construction market is in general
very conservative and it is not
always easy to introduce new ideas
into well-established contexts.
Promotional activities might have to
be undertaken to penetrate the
market.
Promoting and informing
Demonstration projects are neces-
sary. This means that opportunities
to construct “show” buildings must
be found. High standard buildings
are of interest, because they are
appreciated by the general public
and can be designed and built using
simple principles, which can then be
exploited for more economical
housing.
The public needs to be made aware
of the possibilities which are offered
by buildings with arches, vaults and
cupolas. Awareness-raising activi-
ties, showing their full potential, can
be considered around the first
buildings.
Dissemination activities made by
trained professionals is very efficient
and effective.
Ensuring quality
Top quality work is important to gain
people’s confidence. Particular
attention should be paid to the
control of site work: execution,
planing, raw and building materials,
and maintenance of equipment.
Site management
cupolas does not pose any particular
management problems.
However, two points can be of
importance: special equipment and
building seasons.
Special equipment
Special equipment (e.g. arch form-
work) is not found in the normal
building materials trade. Manufactur-
ing it to avoid building delays will
have to be planned in advance.
To ensure a good amortization of the
equipment, planning at the design
stage can allow for using equipment
several times in the same building, or
in different buildings, by repeating
shapes and using standard dimen-
sions.
Building seasons
Even if the materials used are
water-resistant, the building planning
should preferably allow for the
water-proofing to be done before
rainfall periods, which can then be
devoted to inner finishing works.Quality of finishings, a major
asset
Good organization enables work to
be carried out quickly; site of a
house built in 24 hours

SELECT BIBLIOGRAPHY
Office building of the Center of Energy Studies at the Indian Institute of Technology, New Delhi, India
ADAUA. Rapport sur les techniques de construction mises au point par l’ADAUA entre 1977 et 1982 pour la promotion des
matériaux locaux africains. ADAUA, 1982.
Besenval R. Technologie de la voûte dans l’Orient ancien. Tome 1 and 2. “Synthése n° 15”. France, Paris, Editions Recherche sur
les Civilisations, 1984. Tome 1 : 196 pp., tome 2 : 224 pp.
CRATerre, Doat P., Hays A., Houben H., Matuk S., Vitoux F. Building with earth. India, New Delhi, The Mud village society, 1991.
284 pp.
CRATerre, Houben H., Guillaud H. Earth construction, a comprehensive guide. United Kingdom, London, Intermediate Technolo-
gy Publications, 1994.
CRATerre : Dayre M., Doat P., Estève J., Guillaud H., Houben H., Joffroy Th., Rollet P. Toitures en terre. Tome 1. Arcs, voûtes et
coupoles. Paris, France, Rexcoop, 1986. 247 pp.
Dellicour O., El Jack K., Posma L., de Walick P. Le centre de formation agricole de Nianing. Sénégal, Dakar, Dakar Regional Office
for Education in Africa, 1978.
Department of Housing and Urban Development, Office of International Affairs. Mud brick roofs. Ideas and methods exchange. n°
42. USA, Washington, Department of Housing and Urban Development, Office of International Affairs, 1957. 14 pp.
Development Workshop. Les toitures sans bois, guide pratique. France, Lauzerte, Development Workshop, 1990. 77 pp.
Fathy H. Architecture for the poor. An experiment in rural Egypt. USA, Chicago, The University of Chicago Press, 1973.
194 pp. + annexes.
Norton J., Tunley P. Vulgarisation de la construction de voûtes et coupoles au Sahel. Phase 1 : l’identification de besoins.
Suisse, Gland, L’alliance mondiale pour la nature (UICN), Programme Sahel, 1990. 46 pp.
Steele J. Hassan Fathy. Architectural monographs 13. United Kingdom, London, Academy Editions, 1988.

REFERENCES AND SOURCES
Unless otherwise stated, all photographs are by the author. Illustrations: Patrick Idelman.
From left to right and up to down.
Front cover: Construction of a 9 m diameter “star” cupola in compressed earth blocks, Calvi, Corsica, France.
p.2 The town of Thera, on the island of Santorin in the Cyclades, Greece.
p.3 Elevation of the “Andrioli house”, Fayoum, Egypt, 1984, in Hassan Fathy, Architectural Monographs, see bibliography. p.4
House built in adobe bricks near Aswan, Egypt; photo: P. Doat.
p.5 Dar al Islam community building, Abiquiu, New Mexico, USA; a project of architect Hassan Fathy; photo: P. Odul.
Postage stamp issued in Niger in 1992 on the subject of “Woodless Construction”.
p.6 Experimental building at the Rural Housing Research Centre, Dakar, Senegal.
Information and reception centre of Auroville , India; architects: S. Ayer-Guigan and S. Maini; photo: S. Maini.
p.7 Interior of St. Bartholomew church, Zaria, Nigeria.
House built using principles suggested by the “Woodless construction” project, Niger, designed and built by P. Tunley of
Development Workshop; photo: A. Douline.
p.8 Arcatures of provisional mausoleum for Indira Gandhi, India; architects: S. Patara; photo: H. Guillaud.
Rural house in the Dades valley, Morocco.
Interior of reception building, “Village au bout du monde”, near Mâcon, France.
Interior of 24-hour house, Grenoble, France.
p.11 Rural housing on the shores of Lake Titicaca, Bolivia; photo: Th. David.
Adobe vaulting cells on palm trunks, Marrakesh, Morocco; photo: P. Doat.
Administrator’s accommodation, training centre for rural supervisors, designed and built by ADAUA, Kamboincé,
Burkina Faso.
Barn, Causse Méjean, France; photo: G. Beraldin.
Farm in the Qeuyras region, France.
p.12 Village Development Centre built using principles suggested by the “Woodless construction” project, Niger, designed
and built by P. Tunley of Development Workshop; photo: A. Douline.
p.13 Private house, Marrakesh, Morocco, designed and built by architect E. Mouyal.
p.14 Exhibition centre, Janadriyah, Saudi Arabia, designed and built by CRATerre-EAG.
p.18 Making special adobe blocks for the construction of cupolas, Marrakesh, Morocco.
p.19 Multi-layer water-proofing, PanAfrican Development Centre, designed and built by ADAUA, Ouagadougou, Burkina
Faso.
Maintaining the earth render of the roof of the Zaria mosque of the Jos museum, Nigeria.
Dome and water-spout of house in the town of Tozeur, Tunisia.
Tiled roof cover of small church on the island of Santorin, Greece.
p.20 Wooden formwork, Ivory Coast; photo: Ph. Romagnolo.
Corbelled arches, Passamainti, Mayotte.
Metal formwork, Auroville, India; photo: S. Maini.
Brick formwork, building exercise, School of Architecture, Grenoble, France.
Construction with a sliding formwork, CSTB, Grenoble, France.
p.21 Building a barrel vault in “slices” using a light-weight guide, building exercise, Grenoble School of Architecture, France.
Building a squinch vault, Tabas region, Iran; photo: Abedini Rad.
Building a cupola using increasingly inclined ring-courses, near Mâcon, France.
p.22 Building a cupola using a guide, Office building, IIT, architect: G. Minke, energy concept: N.K. Bansal, India; photo: G.
Minke.
Builders’ training on the site of the 24-hour house, built by CRATerre-EAG with AFPA, (the Adult Professional
Training Association), Grenoble, France.
Idem.
p.23 Site of the 24-hour house.
Private house, Marrakesh, Morocco, designed and built by architect E. Mouyal.
p.24 Office building financed by GTZ/GATE; architect: G. Minke, GhK, Germany; energy concept: N.K. Bansal, IIT, India;
photo: G. Minke.
Back cover: Stages in the construction of the 24-hour house, CRATerre-EAG, Illustration: J. Esteve.

BASIN NETWORK

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vaults and cupolas
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WHO MAY BE INTERESTED IN THIS BOOKLET?
Decision-makers, architects, engineers, project managers, building entrepreneurs,
and all who wish to know more about building with arches, vaults and cupolas.
WHAT YOU CAN FIND IN THIS BOOKLET?
Basic information about building with arches, vaults and cupolas.
The advantages and limitations of arches, vaults and cupolas.
Recommendations, bibliographic references and addresses for getting more informa-
tion.
WHAT YOU WILL NOT FIND IN THIS BOOKLET?
Detailed technical information.
Information relating to local conditions.

Building with arches_vaults_cuppolas 1994

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